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 A122060 Position in decimal expansion of 1/n where repetition begins. 1

%I

%S 2,3,2,4,3,3,7,5,2,3,3,4,7,8,3,6,17,3,19,4,7,4,23,5,4,8,4,11,29,3

%N Position in decimal expansion of 1/n where repetition begins.

%C If 1/n = 0.XYYYYY... then sequence gives index of first digit of the second Y.

%C a(4) = 4 and a(p) = p for primes p = {7, 17, 19, 23, 29, 47, 59, 61, 97, ...} = A001913(n) Cyclic numbers: primes with primitive root 10. - _Alexander Adamchuk_, Jan 28 2007

%F a(n)=A121341(n)+2 if 1/n terminates, else a(n)=A121341(n)+1. - _R. J. Mathar_, Sep 20 2006

%e a(4) = 4 because in 0.2500 the zero begins repeating at the fourth position.

%e a(17) = 17 because 0.05882352941176470588... begins repeating at the 17th position.

%Y Cf. A001913, A002371.

%K nonn,base

%O 1,1

%A _Ben Paul Thurston_, Sep 14 2006

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Last modified April 18 16:37 EDT 2019. Contains 322209 sequences. (Running on oeis4.)